While cardiac imaging and functional analysis is the largest single nuclear medical imaging application, there remains a tremendous unmet need for improved cardiac imaging and functional analysis systems and methods. This need is exemplified by the fact that historically, for 30%-50% of those stricken with coronary artery (occlusive) disease (CAD), the first symptom of the disease is death. This has motivated considerable effort to develop diagnostic methods and apparatus to detect CAD prior to the onset of fatal symptoms and assist in the development and implementation of preventive measures.
Two strategies are presently used to reduce morbidity and mortality from CAD. The first involves screening for modifiable cardiac risk factors, such as hypertension, elevated serum cholesterol, cigarette smoking, physical inactivity, and diet. The second involves early detection of CAD. The principal tests for detecting CAD include resting and exercise ECGs, which can reveal the presence of myocardial infarctions and inducible myocardial ischemia. Tc-99m myocardial perfusion and computed tomography (CT) calcification scoring can provide visual evidence of plaques in the coronary arteries. Thallium-201 scintigraphy, exercise echocardiography, and ambulatory ECG (Holter monitoring) are less commonly used for screening purposes. None of these strategies has produced a solution to the high incidence of death due to undetected CAD. Accordingly, there remains an unsatisfied need for improved cardiac imaging and functional analysis systems and methods for reducing morbidity and mortality from CAD.